Electrical indicator



Oct. 1l, 1938. BoDDY ELECTRICAL INDICATOR 2 .Sheets-Sheet 1 Filed Sept.15, 1936 lLEONARD BUDDY mm Ot. 11, 1938. BOBBY 2,133,077

ELECTRICAL INDICATOR Filed Sept. 15, `1936 2 Sheets-Sheet 2 LEONARDBVOVDDY; INVENTOR.

Patented 11, 1938 AUNITED STATES yPil'rlzu'r OFFICEv ELECTRICALINDICATOR Leonard Boddy, Ann Arbor, Mich., assignor to The AndersonCompany, Gary, Ind., a corporation of Indiana Application September 15,1936, Serial No. 100,918

4 Claims.

' paratus.

I am familiar with electrical indicating systems comprising atransmitter or sending unit disposed at the point of manifestation of aphysical force such as temperature, pressure, or liquid head and anindicating unit at a point remote from the transmitting unit butconnected in circuit therewith wherebyI an indication of the variationin the physical force is indicated through corresponding variations incurrentl value transmitted to the indicating unit.

One such'type of transmitter is illustrated in a patent to T. J.Smulski, No. 2,006,608, issued July 2, 1935 wherein the relative warpingoi associated bimetallic elements under thermal change is adapted tocause a series of current pulsations whichv may be transmitted to asuitable indicating unit such as the-type illustrated in a patent to T.J. Smulski, No. 2,022,441, issued November 26, 1935.

'I'hese instruments are primarily adapted to automotive vehicles whereinit is desired to use a minimum amount of current and the apparatus partsmust be extremely, sensitive. Due to the operating requirements of theparts employed, and the variations in material and necessary tolerancesencountered in commercial pro-l duction, I have found that considerablevariation in indication of a given condition will result unlessadjustment means are provided. The present adjustment an'd calibratingmeans required are relatively involved and require considerable time foraccurate adjustment.

Additionally, due to the sensitiveness of the operating partsparticularly whenplaced on an automotive vehicle which is, normallysubjected to considerable vibration, the' manner oi mounting of theparts oi the mechanism is extremely important.

I have disclosed in the present application an indicating system o1' theabove type and particularly a transmitting unit which is susceptible ofand economically manufactured in quantity production. l

Another object of my invention is to provide a 'transmitting unitadapted to electrical indicating systems which can be quickly andaccurately adjusted and calibrated.

Another object of my invention is to provide of a transmitter embo (c1.zoo-122) a transmitter adapted to electrical indicating systemshaving'the parts mounted so as to be relatively uniniiuenced byvibration and the like.

Another object of my invention is to provide a transmitter forelectrical indicating systems which can initially be accurately adjustedand calibrated, which is relatively uninfiuenced by temperaturevariation, and which will continue `giving accurate indication over along period of use.

Another object of my invention is to provide an electrical indicatingsystem having a simple and eiiicient transmitter, and `wherein a majorportion of the transmitter parts are adaptable as a unit to transmittersof diffrent types such as liquid level, oil pressure and the like.

Other objects of my invention and the invention itself will becomeincreasingly apparent with a consideration of the following descriptionand drawings wherein:

Fig. 1 is an elevationalview partially in section ng my invention;

Fig. 2 is a section taken 'along the line 2-2 of Hg. f

Fig. 3 is a section taken along line 3 3 of Fig. 1: i

Iliigs. 4 and 5 are elevational views of parts of the transnutter orFig. 1; v

Fig. 6 is a diagrammatic view of an indicating system embodying myinvention;

Fig. 'l is a modified form of transmitter; and

Fig. 8 is a circuit diagram with parts illustrated in conventional form.

Referring now to the drawings, I havefindicated generally at l the ltopwall of an automotive vehicle gasoline tank or similar liquid containeron which is mounted a transmitter unit generally indicated at Il, thetransmitter being connected through a wire l2 with an electro-responsiveindicator I3 which is connected by grounds indicated at I6 and I1. Themanner of wiring an electrically operable indicating system of this typeis well known and a further description is not believed necessary.

The electro-responsive indicator Il mafbef any well known type which isactuate either by intermittent current pulsations or b a continuouscurrent of varying intensity. Th transmitter Il comprises an enclosedhousing p rtion 20 and a depending generally channel-sha ed arm- 2|. Thecontainer wall l0 is perforated an the arm 2l fand a portion of thehousing is projec d there/I adapted to actuate a generally verticallydisposed lever 25. The lever 25 adjacent its upper end is provided withan elongated kperforation 26 having substantially parallel sides for thereception of ,a pin 21 rigidly secured to depending arm 2 I, 'Ihe upperend of lever 25 is secured to'a diaphragm 28, the diaphragm beingprovided with a central perforation within which is secured, in asuitable manner as by soldering, a metal washer 29, the washer beingslotted whereby a neck portion of lever 25 may project upwardlytherethrough and also through an operating arm 30 which is soldered orotherwise secured to the diaphragm 28. 'Ihe neck portion of lever 25 isthen flanged over whereby the lever and arm 30 are rigidlyinterconnected with each other and with the diaphragm, and movement oflever 25 will correspondingly move arm 3U.

.The diaphragm is provided with an upstanding peripheral flange and isadapted to be seated within and secured by soldering or the like to agenerally cup-form portion 3l of the housing. The housing portion 3l hasa perforated base permittingthe lever arm to be projected therethroughand since the pin 21 prevents longitudinal movement of lever 25 it isconstrained to rock about pin 21 under lateral movement of the.lowermost end of the lever effected by the camming face 24 of the floatelement.

A spring 32 is secured to the lever 25 adjacent the perforation 26 andto the depending .arm I I laterally of the point of attachment to thelever whereby there will always be a tendency to rotate the lever in acounter-clockwise direction as viewed in Fig. 1 insuring that the leverwill always be maintained in contact with the camming surface of thefloat element 23 and the iioat incontactwith the liquid surface.

It will now be understood that when the container is substantiallyfilled with liquid that the fioat element will be in a substantiallyhorizontal position or the float will be above the point of supportofthe fioat element and the camming surface thereof will rock the lever24 laterally to a considerable degree and in turn the associatedoperating arm 30 will be rocked so that its free end moves upwardly. Asthe liquid level within the container decreases, the degree throughwhich the lever 24 is rocked decreases and the free end of arm 3U has adefinite position corresponding to a given liquid level and in a mannerto be later described this controls the current passing throughthetransmitter to the indicating unit I 3.

Fig. '7 illustrates a transmitter adapted to be included in a system toindicate fluid pressure, such as oil pressure, the arrangement beingsimilar to that described for indicating liquid level with the exceptionthat a diaphragm directly transmits movement. rather than through anoperating arm. A housing adapted to be mounted at or adjacent lthe oilpump comprises a relatively shallow cup member 4l) havinga centrallydisposed externally threaded stem 4I permitting the housing to besealingly securedl at the oil pump or a convenient place in the oilconduit line.

The stem is centrally bored'for entry of oil to the housing interior.

The cup element 40 has an axially extending peripheral flange aboutwhich transmit movement axially thereof in response to changes in oilpressure.

A transmitter unit generally indicated at 50 is.`

adapted to senda series of current pulsations through the circuit of thesystem proportinal to movement of an element associated therewith andwhich movement is eected by the operating arm 30 of the liquid cntainertransmitter or the diaphragm 42 of the oil pressure transmitter. Theoperation ofthe transmitter unit 50 will now be described.

The unit 50 comprises a circular plate4 5I adapted to be inserted withinthe housing cup portion 3l of the liquid container transmitter andadapted to be gripped by fingers not shown. In a similar manner the unitis adapted to be mounted in the oil pressure transmitter by beingdisposed within the ring element 43 and gripping plate 5I by similar:fingers 52.v The plate 5I is provided with a relatively large andgenerally rectangular perforation 53 and is also provided with anupstanding arm 54 for a purpose to be later described. Two spacedtubular pins 55 and 56 project upwardly from the plate and telescopedover the pins is a copper or the like resilient element 51 having an armprojecting into the plate perforation 53, the arm being bent downwardlygenerally centrally thereof to provide a U shaped abutment 58. Theelement 51 is provided with a lateral extension to which is rigidlysecured a bimetallic strip 59 by an end sulating strip 6I and an element65 formed of copper or the like and having an arm projecting outwardlyinto the plate perforation 53, the arm having a lateral extension towhich is rigidly secured a bi-metallic strip 66 'similar to strip 59 butopposite hand, having a contact 61 on its lower face. An upstandingperforated arm 68 either integral with element 65 or in contacttherewith is also disposed above the second insulating strip 6I.

A third insulating strip 6I and' a similarly formed metal plate are thentelescoped over pins 55 and 56 and the pins are staked or anged over tofirmly mount the above described parts on plate 5I. u

An insulated wire encircles the bimetallic strip 66 forming a heatingcoil 69, one end of thel ed to warp the strip 66 and cause the contactV61 to be moved in correspondence with the current heating value.

A shunt unit 10, best illustrated in Fig. 6, comprises\}a fibre stripencircled by a plurality of turns of wire with the wire ends engagingterminals 1I and 12 slipped over the strip ends. The shunt yunit isadapted to interconnect arms 64 I' and 68 by projecting the terminals 1|and 12 through the arm perforations whereby current may be shuntedaround heating coil 69 in a manner and for a purpose to be laterdescribed.

'Ihe upstanding arm 54 of plate 5I has a horizontally extending portionprovided with a pression spring 15 intermediate the screw headA and arm5l of plate 5i and also provide a resilient clip having aflnger 15engaging a preferably' knurled surfaceof the screw head. The clip ismaintained in place by projecting the screw 1l therethrough and forminga. lip thereon to engage a slot in arm 54.

The operation of the transmitter will now be described. If thetransmitter unit 551s in the liquid level indicating system theoperating arm 30 will engage abutment 58 of element 51 and if employedon the pressure indicating system the diaphragm l2 will engage theabutment but in either case the substantially vertical movement ofabutment 58 will correspond to the height oi the liquid in the containeror the intensity ofthe pressure.

'I'he bi-metallic strip 59 and its contact 85 will be correspondinglymoved and contact 50 will variably press against contact 51 permittingcurrent to traverse the heating coil tending to cause the bi-metallicstrip 65 and contact 51 to move away from contact 50 and break thecircuit. The length oi' time required for separation of the contactswill depend on the pressure between the contacts and since a currentimpulse of this duration will be transmitted to the indicating unit I3it will measure the liquid level or pressure. It the voltage increasesthe contacts will separate more quickly but a current impulse of greatervalue will be transmitted so` that the cumulative value of the currentimpulse in a given short interval will be substantially constant despitevoltage variation.

In Calibrating the transmitter it is necessary to correct the range tocorrespond with the indicating unit minimuml and maximum readings sincethe empty iloat position or minimum pressure position can be checked byadjustment of the indicating unit arm. The transmitter is connectedsubstantially as illustrated in Fig. 6 and the readingV with the shuntunit omitted is checked on a master indicating unit and which willnormally underread. Shunt umts of varyby vibration.

ing resistance are available and one is selectedv Although I have shownand described modincations of my invention, I contemplate that numerousand extensive departures may be made therefrom without departing fromthe spirit ofv my invention and the scope of the appended claims.

Having thus described my invention, what I claim is:

l. An electric circuit controller comprising a support, an arm ilxed tothe support at one end and having a freely movable portion, a thermallyresponsive element supported at one end by the arm and bodily movabletherewith, the thermally responsive element having an opposite endportion movable responsive to thermal change and adapted to form anelectric contact, a second arm ilxed to the support at one end andhaving a freely movable opposite end, a second thermally responsiveelement supported at one end by the second arm and bodily movabletherewith, the opposite end of the second thermally responsive elementbeing movable upon thermal change and being adapted to contact the ilrstthermally responsive element to complete an electric circuit,

lboth thermally responsive elements being substantially equallyresponsive to thermal change to compensate for ambient temperaturevariations, electrical heating means associated with one of saidthermally responsive elements to effect separation of said elements uponenergization of the heating means, means for adjusting the position ofone of said arms-to vary the operation of the thermally responsiveelements, a terminal electrically connected to the thennally responsiveelement having the heating means associated therewith, and a secondterminal'electricaliy connected with the heating means whereby aresistance unit may be detachably inserted between the terminals to varythe current passing through the heating means.

- 2. An electric circuit controller adapted to contral current impulsesin the circuit, said controller comprising a support, a pair of armsiixed at one end to the support and having freely movable portions, apair of thermally responsive elements each secured to a different one ofsaid arms by an endthereof engaging the arm movable portions whereby thethermally responsive elements may be bodily moved with the arms, each ofsaid thermally responsive elements having a freely movable portionprovided with an electric contact and the contacts being engageable tocomplete an electric circuit, means for adjusting the position oi' oneof said arms to vary the operation w of the contacts, the other armbeing movable to efiect engagement o1' the contacts, electrical heatingmeans associated with one of said thermally responsive elementsenergizable to heat its associated element to effect separation of thecontacts, a terminal electrically connected with the velement having theheating means associated therewith, a second terminal electricallyconnected to the heating means, and a resistance unit detachably mountedbetween the terminals to Yvary the current passing through the heating3.l The controller as described in claim 2 and wherein a conductorextending upwardly is electrically connected to one oi' said terminalsand the heating means, and an enclodng housing engageable with thesupport is provided with a contact engageable with the upstandingconductor to transmit current to the controller.

4. The controller as described in claim 2 and wherein an enclosinghousing is provided engageable with the support, together ,withelectrical conducting means accessible externally ot the housingconnected with one of said terminals and the heating means to transmitcurrent to the LIONARDBODDY.

